FRINGE SCIENCE

The Nose Knows: An Electronic Nose

Readers of this blog already know how fiction can inspire real science and we’ve got another example to show you today: the electronic nose. Ray Bradbury’s science fiction classic Fahrenheit 451 features the concept, as does the 1994 children’s film Richie Rich.

In Richie Rich, Professor Keenbeam (who heads the research and development department for the Richs’ company) invents all sorts of technology, including an electronic nose that resembles a hairdryer with a pig’s nose on the front. It sounds strange but it becomes essential to the plot – it saves Richie’s parents from explosives hidden on their airplane. (Richie also uses it to detect what’s in his birthday presents.)

Electronic nose technology started gaining speed in 2001 with the E-nose from Joel White and John Kaeur at Tufts University. That electronic sniffer analyzed changes in stained DNA’s color as a result of exposure to a vapor. A newer electronic nose (ENose) from the Lewis Research Group at Caltech utilizes chemical sensors that are analyzed electronically. The applications of the new nose mimic its use in Richie Rich; it’s been used to detect mines and explosives. The Caltech ENose has also made its way on the International Space Station where it tested cabin air quality for 6 months.

The ENose has its uses and its limitations, of course. The mammalian olfactory system is complex and not easily mimicked. The human nose can distinguish between 10,000 odors. The ENose isn’t quite there yet, explains Nate Lewis, professor and head of the Lewis Research Group. “We will never break down the odor of Coca-Cola into the 200 compounds that are in Coca-Cola. But if you’re in a production line and you’re determining if the Coca-Cola is “good” or “bad,” [then] I don’t need to know what the 200 compounds are to tell you it’s different than the good stuff. This is what electronic noses have been used for.” While a human could detect the scent of Coca-Cola, the ENose is limited to analyzing the changes between good and bad Coca-Cola. But that’s the strength of the ENose as well; humans would have difficulty smelling the good soda from the bad soda. The ENose can also detect smells humans can’t, like mercury.

The ENose has potential to be used as a means of protection from hazardous environments or contaminated food. The device may have been a silly invention in a children’s film, but now it’s a reality with real world applications. And as Lewis explains, this advancement in science is something to get excited over. “I think it’s just important for people to realize that this is a really remarkably exciting time for science. Almost all of these things that we talked about wouldn’t really have been possible 20 years ago. On the electronic nose, it is a combination of materials, of systems, and signal processing that together synergistically make this possible. It’s a combination of what we know about biology, of what we’re learning about chemistry, and our ability to control materials.”